This invention relates to a coupling for connecting a rotating tube cleaning shaft to a tube cleaning machine where high pressure fluid is pumped through the coupling, where the coupling is sealed to contain the high pressure fluid, and where a machine driven rotary flexible shaft passes through the coupling.
The invention has particular application with machines for cleaning the interior of heat exchanger tubes to maintain operational efficiency. Rotating brushes or other tools and flushing water are used for this kind of tube cleaning. A common type of heat exchanger has a bundle of tubes fixed at opposite ends in headers. Typically, untreated cooling water flows through the interior of the tubes and exchanges heat with water or some other fluid on the outside of the tubes which is at a different temperature than the water flowing on the inside of the tubes. As is well known, if the water flowing through the tubes is dirty or untreated or inadequately treated for minimizing precipitation of minerals, a mineral deposit and dirt will gradually accumulate on the inside of the tubes. Accumulated mineral and dirt in the tubes is removed by means of a tube cleaning machine propelling a rotating brush or other cleaning tool through each tube to dislodge mineral and dirt, and carrying dislodged material away in a flow of pressurized cleaning water.
In a tube cleaning machine of this kind, a cleaning tool such as a brush is mounted at an end of a rotating shaft encased within a sheath, and cleaning fluid typically pressurized water passes through a sheath interior passage into the heat exchanger tube. Combined action of rotating tool and pressurized water accomplishes the desired tube cleaning in removing mineral deposits and dirt.
In this operational setting, there is need for a fluid tight drive shaft coupling for quickly and easily connecting the rotary shaft to the tube cleaning machine that provides rotary drive and pressurized water.